Basically after finishing LL:FR is it worth progressing ont o LL:RA or getting one of the readers from the same series? Thing is I can read Latin, being a second year etc, it's just a little slow and I'm looking to revise before term starts, currently on Capitulum XXIV of LLFR, I'm wondering whether it's a good purchase for someone at my level right now or if I should just pick up one of the readers.

Thing is term starts soonish and I'm juggling this and reading the Iliad, is Roma Aeterna a massive headache?

I think the route you go should depend on your interest. I don't have it in front of me, but I recall that Roma Aeterna gets a lot harder a lot faster than Familia Romana. I assume this is because Orberg tries to adapt original authors as much as possible. There is a lot of new vocabulary and the chapters are quite long. The early parts of the book are all about Roman history and adapted from Livy and similar authors. Personally, I find this boring, but many disagree.

The only other Orberg reader I've used is his short version of the Gallic Wars. I actually used this before I started the main course, so I can't say how the transition is. Generally, it's unadapted (though excerpted) Caesar with copious notes. It's probably easier in some ways than Roma Aeterna, given that you can stick with the same author and that Caesar likes to keep things straight-forward.